1. Field of the Invention
The present invention relates to a power factor correction circuit, and more particularly, to a power factor correction circuit capable of correcting a power factor of a power converting module through increasing the average value of an input current by switching a main switching element of the power converting module on the basis of a reference wave having a slope based on a first signal and an error voltage, in particular, by limiting a switching frequency on the basis of a reference wave having a slope based on a second signal lower than a first signal and an error voltage when the switching frequency of the main switching element increases because an input voltage of the power converting module is low.
2. Description of the Related Art
In recent years, the stable supply of power has become an issue due to an increase in power consumption generated by using an electronic apparatuses. Therefore, countries around the world have been strengthening restrictions relating to a harmonic component generated by an input terminal of the electronic apparatus in order to minimize an influence on a power supply line of the electronic apparatus and minimize interference with other electronic apparatuses. In order to satisfy the restrictions on the generation of the harmonic component, a power factor correction circuit is required.
In the power factor correction circuit used in the power converting module such as a boost-type converter according to the related art, a boundary conduction mode (BCM) is generally used due to the ease of the implementation of zero voltage switching (ZVS). However, in the case of the boundary conduction mode, a switching loss increases because the switching frequency increases when a current required for an input is small or an input voltage is low, and as a result, efficiency decreases.